[RE-wrenches] Tilt Racking vs Roof Mount for Shedding snow

[Dave]

Dan,

 

What do you mean by "tilt up racking". Would an example be a rack that adds 15 degrees to a 5/12 roof? Good idea (as long as wind load is taken care of) for cold snow country (certainly for off grid) to get the tilt angle higher which helps with snow shedding. BUT if it's super cold like this winter here in northern New England nothing helps as much as a snow rake. 

 

On a side note. I had a couple of monitored grid tied systems with second story roof top arrays that produced very little power from January through second week of March. 80% less kWh than similar first story roof top arrays where the homeowner raked off snow. It was so cold that in one period this winter that it did not get over 30 degrees F for 48 consecutive days here, with many nights at 15 to 30 below zero. February was the coldest on record (since 1886) with temps that were 15 degrees below average for the month. No snow shedding going on at all. 

 

On another type of array. My adjustable ground mount here set at 90 degrees had a great winter as I regularly saw 1,750 to 1,950W out of my Apollo CC from a 1,440W array on sunny days because of MPPT and the reflective bounce of sunlight off the snow in front of the array. I never have to touch those modules from mid November, when I tilt them to 90 degrees, until after it stops snowing significantly (mid April usually).

 

Best,

Dave

 

David Palumbo 

Independent Power LLC

462 Solar Way Drive

Hyde Park, VT 05655

802-888-7194

 

 

 

From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of dan at foxfire-energy.com
Sent: Friday, March 27, 2015 8:19 AM
To: RE-wrenches
Subject: [RE-wrenches] Tilt Racking vs Roof Mount for Shedding snow

 

 

 

Hi Guys, I have a customer who seems convinced that tilt up racking sheds snow better than conventional roof mounted arrays (irregardless of angle or panel manufacturer). Anyone else find this is true? Thanks db

 

 

 

Dan Brown
Foxfire Energy Corp.
Renewable Energy Systems
(802)-483-2564
www.Foxfire-Energy.com
NABCEP #092907-44



 

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